iOS DeveloperFlipboard

Building iPhone/iPad apps with UIKit and Foundation
Performance and memory tuning with Instruments and Shark
Using gdb to diagnose and squash bugs
Integrating with web services
Writing clean, maintainable code while rapidly iterating and shipping

Bonus points for:

Using Core Animation to create eye-popping effects and interfaces
Multithreading, NSOperationQueue and Blocks/GCD.